Bioelectronics-embedded injectable hydrogel for neural regeneration

神经损伤（例如脊髓损伤）是一个衰弱的健康问题，由于有限的再生能力， 神经系统的能力。再生受损神经组织的一种潜在方法是递送 能够分化成神经元并与宿主融合的干细胞。为了提高细胞活力， 为了定位，已经探索了可注射水凝胶作为NSC递送载体。然而，大多数注射 水凝胶缺乏微孔结构，不能促进细胞-细胞相互作用，而细胞-细胞相互作用对于神经细胞的生长是必需的。 分化和功能性神经组织形成。 在这项研究中，我们将开发一种用于NSC递送的可注射微孔水凝胶， 再生神经组织可注射微孔制剂由复合微凝胶制成， 甲基丙烯酸化明胶（GelMA）和甲基丙烯酸化透明质酸（MeHA）。这些微凝胶形成了一个整体 通过双重交联机制制备微孔水凝胶：（i）甲基丙烯酸酯的快速紫外光聚合 和（ii）通过微生物转氨酶（mTG）的酶促交联，其也促进组织粘附。的 用微凝胶注射的NSC被封装在微凝胶之间的间质微孔中， 将迅速扩散，并分化成具有适当细胞间相互作用的神经元，从而产生功能性神经元。 神经网络的这与传统的可注射水凝胶形成对比，在传统的可注射水凝胶中，包封的细胞被 被聚合物链捕获，并禁止形态变化和细胞-细胞相互作用。我们 假设增强的细胞间相互作用将导致更多的电活性神经元和功能性神经元， 神经网络。我们将采用创新的生物电子网格（BioEM），以实现实时读数， 整个支架的神经活动。来自BioEM的数据将允许对以下数据进行统计比较： 不同的微凝胶配方，并告知新的设计迭代。 为了实现本研究的主要目的，我们首先合成并优化了可注射的 微凝胶在紫外线照射下快速固化，具有高细胞活力、细胞铺展和神经元生长， 包封的NSC的分化。同时，将制造BioEM，其将与 基于微凝胶的水凝胶具有包封的NSC的高细胞活力。最后，BioEM将用于 监测来自包封在水凝胶中的NSC的功能性神经网络的发育。 到本项目结束时，将开发一种新型微孔水凝胶配方， 来输送神经干细胞用于神经组织再生。通过BioEM嵌入的生物电子学将允许 连续的电生理学读数，这将为水凝胶微凝胶的未来迭代提供信息。系统 在体外证明功能性神经网络的研究将是临床翻译的有希望的候选者。

Neural injuries (e.g. spinal cord injury) are a debilitating health problem due to the limited regenerative capacity of the nervous system. One potential way of regenerating damaged neural tissues is the delivery of stem cells that can differentiate into neurons and integrate with the host. To increase the cell viability and localization, injectable hydrogels have been explored as NSC delivery vehicles. However, most injectable hydrogels lack microporous structures and fail to promote cell-cell interactions which are essential for neural differentiation and functional neural tissue formation. In this research we will develop an injectable microporous hydrogel for NSC delivery that can regenerate neural tissues. The injectable microporous formulation is made of composite microgels, composed of methacrylated gelatin (GelMA) and methacrylated hyaluronic acid (MeHA). These microgels form a bulk microporous hydrogel via a dual crosslinking mechanism: (i) rapid UV photopolymerization of methacrylates and (ii) enzymatic crosslinking by microbial transglutaminase (mTG) which also promotes tissue adhesion. The NSCs that are injected with microgels are encapsulated in the interstitial micropores between microgels, and will spread rapidly, and differentiate into neurons with proper cell-cell interactions, resulting in a functional neural network. This is contrasted with the traditional injectable hydrogels in which the encapsulated cells are entrapped by the polymer chains and prohibited for morphological changes and cell-cell interactions. We hypothesize that the enhanced cell-cell interactions will lead to more electrically-active neurons and functional neural networks. We will adopt an innovative Bioelectronic Mesh (BioEM) to achieve real-time readouts of neural activity throughout the scaffolds. Data from the BioEM will allow for statistical comparisons between different microgel formulations and inform new design iterations. To achieve the main objective of this research, we will first synthesize and optimize the injectable microgels which rapidly cure upon UV irradiation with high cell viability, cell spreading and neuronal differentiation of the encapsulated NSCs. In parallel, BioEM will be fabricated which will integrate with the microgel-based hydrogel with high cell viability of the encapsulated NSCs. Finally, BioEM will be used to monitor the development of functional neural network from the NSCs encapsulated in the hydrogel. By the end of this project, a novel microporous hydrogel formulation will be developed with the potential to deliver NSCs for neural tissue regeneration. Embedded bioelectronics via the BioEM will allow for continuous electrophysiological readouts that will inform future iterations of the hydrogel microgel. Systems that demonstrate functional neural networks in vitro will be promising candidates for clinical translation.